<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8" />
		<title>5.简单模拟一下_data里的事</title>
	</head>
	<body>
		<script type="text/javascript" >

			let _data = {}

			Object.defineProperty(_data,'n',{
				get(){
					return 1
				},
				set(value){
					console.log('_data中的n被改了，我要去更新页面！',value)
				}
			})

		</script>
	</body>
</html>